Adamantane is a compound which is obtained by isomerizing, in the presence of a catalyst, trimethylene norbornane (hereinafter sometimes referred to as “TMN”) obtainable by hydrogenating dicyclopentadiene (hereinafter sometimes referred to as “DCPD”). In an industrial process for producing the same, aluminum chloride has heretofore been employed as a catalyst. However, in the case of producing adamantane in the presence of aluminum chloride as a catalyst, it is necessary to use a large amount thereof and besides, the catalyst is not reusable because of complex formation with heavy components during the course of reaction. Accordingly, the foregoing process, when being employed therefor, brings about the formation of a large amount of waste aluminum components, whereby the waste treatment thereof gives rise to a problem of environmental pollution. In addition, high corrosiveness of aluminum chloride necessitates the use of an expensive corrosion-resistant materials of construction. Moreover, aluminum chloride, when used therefor, causes the resultant adamantane to be colored and thereby brings about such disadvantages that recrystallizing step and decolorizing step by means of activated carbon or the like are required and hence, a post treatment is made intricate.
On the other hand, a solid-acid catalyst is known which comprises an active metal such as platinum, rhenium, nickel or cobalt each being supported by impregnation method on zeolite that has been subjected to cation exchange by the use of a rare earth metal or an alkaline earth metal {refer to Japanese Patent Publication No. 2909/1977 (Showa 52)}. However, even in the case where the aforesaid solid-acid catalyst is employed, the yield of adamantane is low, unless hydrogen chloride is allowed to coexist therewith, for instance, conversion of TMN of 79.5%, selectivity to adamantane of 10.1% and yield of adamantane of 8.0%. Therefore, hydrogen chloride is indispensable for the isomerization, but high corrosiveness of hydrogen chloride necessitates the use of an expensive corrosion-resistant materials of construction {(refer to Japanese Patent Publication No. 2909/1977 (Showa 52)}.